Confirmations are needed so that you know that the change of a double spend is close to nothing. And that isn't as easy as you think, it's quite a hassle and not worth if used for small transactions. The risk is for the seller, but he can take into account the change of some losses because of this. And with bigger transactions it would be wise to wait to see a few confirmations.
The risk of double spend is minimal. Cheques and credit payments can bounce or be reversed or somebody might pay you with fake money which you don't spot. All forms of payment have weaknesses but Bitcoin's are minimal at best and the vast majority of the time are without problems.
Confirmations are needed so that you know that the change of a double spend is close to nothing. And that isn't as easy as you think, it's quite a hassle and not worth if used for small transactions. The risk is for the seller, but he can take into account the change of some losses because of this. And with bigger transactions it would be wise to wait to see a few confirmations.
You don't need to wait. The confirmations already make it close to nothing. It's not as difficult and as big a problem as you think. Payment processors will probably insure against any loses within regards to this anyway, just like credit cards do, so moot point.